c# - PictureBox 可以在 Windows 应用程序中显示动画 GIF 吗？

Question

我想在.Net Winform 中显示一个动画 gif。这个怎么做？

我以前使用过 VB 6.0。

Answer 1

1. 将 aPictureBox放在表单上，​​然后指定一个带有 Gif 扩展名的图片文件。或者：

2. 以编程方式将 gif 图像加载到PictureBox带有代码的帧中，这是 Gif 类：

VB.NET

 Imports System.Drawing.Imaging
 Imports System.Drawing

 Public Class GifImage
    Private gifImage As Image
    Private dimension As FrameDimension
    Private frameCount As Integer
    Private currentFrame As Integer = -1
    Private reverse As Boolean
    Private [step] As Integer = 1

    Public Sub New(path As String)
        gifImage = Image.FromFile(path)
        'initialize
        dimension = New FrameDimension(gifImage.FrameDimensionsList(0))
        'gets the GUID
            'total frames in the animation
        frameCount = gifImage.GetFrameCount(dimension)
    End Sub

    Public Property ReverseAtEnd() As Boolean
        'whether the gif should play backwards when it reaches the end
        Get
            Return reverse
        End Get
        Set
            reverse = value
        End Set
    End Property

    Public Function GetNextFrame() As Image

        currentFrame += [step]

        'if the animation reaches a boundary...
        If currentFrame >= frameCount OrElse currentFrame < 0 Then
            If reverse Then
                [step] *= -1
                '...reverse the count
                    'apply it
                currentFrame += [step]
            Else
                currentFrame = 0
                '...or start over
            End If
        End If
        Return GetFrame(currentFrame)
    End Function

    Public Function GetFrame(index As Integer) As Image
        gifImage.SelectActiveFrame(dimension, index)
        'find the frame
        Return DirectCast(gifImage.Clone(), Image)
        'return a copy of it
    End Function
End Class

C＃

using System.Drawing.Imaging;
using System.Drawing;

public class GifImage
{
    private Image gifImage;
    private FrameDimension dimension;
    private int frameCount;
    private int currentFrame = -1;
    private bool reverse;
    private int step = 1;

    public GifImage(string path)
    {
        gifImage = Image.FromFile(path);
        //initialize
        dimension = new FrameDimension(gifImage.FrameDimensionsList[0]);
        //gets the GUID
        //total frames in the animation
        frameCount = gifImage.GetFrameCount(dimension);
    }

    public bool ReverseAtEnd {
        //whether the gif should play backwards when it reaches the end
        get { return reverse; }
        set { reverse = value; }
    }

    public Image GetNextFrame()
    {

        currentFrame += step;

        //if the animation reaches a boundary...
        if (currentFrame >= frameCount || currentFrame < 0) {
            if (reverse) {
                step *= -1;
                //...reverse the count
                //apply it
                currentFrame += step;
            }
            else {
                currentFrame = 0;
                //...or start over
            }
        }
        return GetFrame(currentFrame);
    }

    public Image GetFrame(int index)
    {
        gifImage.SelectActiveFrame(dimension, index);
        //find the frame
        return (Image)gifImage.Clone();
        //return a copy of it
    }
}

C#用法：

打开一个 Winform 项目，拖放一个PictureBox、一个 Timer 和一个 Button，GifImage.cs类如上所示。

public partial class Form1: Form
{
    private GifImage gifImage = null;
    private string filePath = @"C:\Users\Jeremy\Desktop\ExampleAnimation.gif";
     
    public Form1()
    {
        InitializeComponent();
        //a) Normal way
        //pictureBox1.Image = Image.FromFile(filePath);

        //b) We control the animation
        gifImage = new GifImage(filePath);
        gifImage.ReverseAtEnd = false; //dont reverse at end
    }

    private void button1_Click(object sender, EventArgs e)
    {
        //Start the time/animation
        timer1.Enabled = true;
    }

    //The event that is animating the Frames
    private void timer1_Tick(object sender, EventArgs e)
    {
        pictureBox1.Image = gifImage.GetNextFrame();
    }
}

Answer 2

在@JeremyThompson 的回答上进行开发我想添加一个代码片段来展示如何实现第一种方法，因为它更简单，并且不需要您手动为 gif 设置动画，因为它PictureBox具有内置功能处理这种情况。只需将 a 添加PictureBox到您的表单中，然后在表单构造函数中将图像路径分配给PictureBox.ImageLocation

C＃

 public PictureForm()
 {
      InitializeComponent();
      pictureBoxGif.ImageLocation = "C:\\throbber.gif";
 }

VB.Net

Public Sub New()
    InitializeComponent()
    pictureBoxGif.ImageLocation = "C:\throbber.gif"
End Sub

在我看来，这是一个更简单的解决方案，尤其是对于刚接触 .NET 的人。

Answer 3

我已经玩过这个，如果您不在同一个线程上执行另一个长时间运行的操作，动画就会播放。当您执行另一个长时间运行的操作时，您希望在另一个线程中执行它。

最简单的方法是使用 BackgroundWorker 组件，您可以将其从工具箱拖到表单上。然后将长时间运行的操作代码放入 BackgroundWorker 的 DoWork() 事件中。最后一步是通过调用 BackgroundWorker 实例的 RunWorkerAsync() 方法来调用您的代码。